Approaching five weeks of age, the chicks are within a few days of being able to take flight for the first time, and the remaining down feathers are usually largely restricted to the lower back, lower legs, and crown.  Here the female is providing another morning feeding and pauses to look to her left.

Day 33 – ‘the age of the white pantaloons’.  This may happen a day or two earlier or later, but most chicks do go through this phase where they have large fluffs of down conspicuously surrounding their legs, much more prominently than anywhere else on their bodies.  

This image captures a rare moment with both adults in the nest box; the male is on the ledge with leg bands!

By day 29, the chicks often have their faces largely free of down, giving them a white-capped appearance.  On their backs, the remaining down often appears to be clumped together in certain areas, with extensive areas instead revealing the dark juvenile feathers. 

It’s often around day 30 that the chicks seem to turn into “real” peregrines almost overnight, very rapidly losing much of the down on their breast, thus revealing the heavily streaked breast feathers they will be carrying for the next year. 

By day 31, the chicks often become actively interested in losing their down, preening themselves and sometimes ending up with feathers stuck to their beak as a result.  From the back they are looking increasingly dark, with the wing feathers approaching full length. 

As they approach four weeks of age, the chicks are rapidly growing their juvenile feathers both below and above, and are looking visibly darker with each passing day.

At day 28, the chicks are nearing the midpoint of their transition from down-covered chick to juvenile-plumaged fledgling, and are nearly full-grown in terms of body size and weight.